more SkSL interpreter performance work

Bug: skia:
Change-Id: I21da1f1473fb73e8ba1371e7301f3fff2e33e8cc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212199
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Mike Reed <reed@google.com>
7 files changed